Rowbotham, Thomas Leeson; Rowbotham, Thomas Charles Leeson [Ill.]; Dalziel, George [Ill.]: The Art Of Sketching From Nature (London, 1852)

28

ON THE REPRESENTATION OF

ON THE REPRESENTATION OF HORIZONTAL STRAIGHT LINES
—WHETHER PARALLEL, PERPENDICULAR, OR OBLIQUE,
TO THE PLANE OP THE PICTURE.

A horizontal right line has, with respect to the plane
of the picture, one of three positions. It is either parallel
to it, or oblique to it, or perpendicular to it. The follow-
ing supposition will explain what is meant by these three
relations of a horizontal line.

Let the student suppose himself sitting with his back
ag&inst one of the walls of a rectangular room. The wall
opposite to him is parallel to that behind him, and conse-
quently to the plane of his picture in that position. The
two remaining walls being at right angles with that
opposite to him, arc evidently perpendicular to the plane
of the drawing, and all horizontal right lines on those two
walls are also perpendicular to that plane, and will appear
to tend towards a point immediately opposite to his eye.

FIG. 11.